The Global Lung Initiative Race-neutral Equations and Lower Limits of Normal Refine Baseline Lung Allograft Dysfunction Risk Stratification after Lung Transplantation

Baseline lung allograft dysfunction (BLAD) contextualises peak post-transplant lung function, but the prognostic impact of GLI-2012 versus GLI-2022 and respective 80% predicted versus LLN classification remains unclear. In 1283 adult bilateral first lung transplant recipients from three European centres, baseline FEV₁ was defined as the mean of the two highest post-transplant values at one year after transplantation or beyond, with corresponding FVC values. Percent-predicted values and LLN were calculated using GLI-2012 and GLI-2022, and subnormal lung function was evaluated for graft survival, CLAD-free survival, and survival after CLAD diagnosis using Kaplan-Meier and adjusted Cox models. GLI-2022 classified fewer patients as below normal than GLI-2012. Using the 80% threshold, 412 patients (32%) were classified as BLAD by GLI-2022, while 112 (9%) were reclassified from BLAD to No BLAD compared with GLI-2012. Using LLN, 300 patients (23%) were Below LLN by GLI-2022, while 146 (11%) were reclassified from Below to Above LLN. Outcomes after normality reclassification varied by endpoint. Persistent BLAD and Below LLN were associated with worse graft and CLAD-free outcomes, with risk further refined by FEV₁/FVC impairment patterns and BLAD severity. These findings support BLAD's prognostic relevance and the importance of using race-neutral equations and LLN-based definitions after transplantation.